Wnt11 promotes BMP9-induced osteogenic differentiation through BMPs/Smads and p38 MAPK in mesenchymal stem cells.

Bone morphogenetic protein 9 (BMP9), as one of the most potent osteogenic factors, is a promising cytokine for bone tissue engineering. Wnt11 can regulate the development of the skeletal system and is related to high bone mass syndrome. However, the effect of Wnt11 on BMP9-induced osteogenic differentiation remains unknown. In this study, we investigated the relationship between Wnt11- and BMP9-induced osteogenic differentiation in mesenchymal stem cells (MSCs). We recapitulated the osteogenic potential of BMP9 in C3H10T1/2 cells. The messenger RNA expression of Wnt11 is detectable in the available progenitor cells, and BMP9 can obviously increase the protein level of Wnt11 in these cells. Exogenous Wnt11 potentiates the effect of BMP9 on increasing alkaline phosphatase (ALP) activities, the expression of osteopontin (OPN), and Runt-related transcription factor 2 (Runx2), so does matrix mineralization in C3H10T1/2 cells. Although Wnt11 cannot increase the BMP9-induced ectopic bone formation, it can increase the bone density induced by BMP9 apparently. Wnt11 increases the level of p-Smad1/5/8, as well as p-p38. Meanwhile, Wnt11 promotes the effect of BMP9 on increasing the levels of p-Smad1/5/8 and p-p38. Inhibition of p38 decreases the BMP9-induced ALP activities, the expression of OPN, and the mineralization in C3H10T1/2 cells. However, all of these effects of the p38 inhibitor on BMP9-induced osteogenic markers can be almost reversed by the overexpression of Wnt11. Our findings suggested that Wnt11 can enhance the osteogenic potential of BMP9 in MSCs, and this effect may be partly mediated through enhancing BMPs/Smads and the p38 MAPK signal, which was induced by BMP9.

Zhu JH ，Liao YP ，Li FS ，Hu Y ，Li Q ，Ma Y ，Wang H ，Zhou Y ，He BC ，Su YX ... -  《-》

P38 and ERK1/2 MAPKs act in opposition to regulate BMP9-induced osteogenic differentiation of mesenchymal progenitor cells.

Zhao Y ，Song T ，Wang W ，Wang J ，He J ，Wu N ，Tang M ，He B ，Luo J ... -  《PLoS One》

CREB/Wnt10b mediates the effect of COX-2 on promoting BMP9-induced osteogenic differentiation via reducing adipogenic differentiation in mesenchymal stem cells.

Bone morphogenetic protein 9 (BMP9) is one of the most potent osteogenic factors, which may be a potential candidate for bone tissue engineering. However, the osteogenic capacity of BMP9 still need to be further enhanced. In this study, we determined the effect of Wnt10b on BMP9-induced osteogenic differentiation in mesenchymal stem cell (MSCs) and the possible mechanism underlying this process. We introduced the polymerase chain reaction (PCR), Western blot analysis, histochemical stain, ectopic bone formation, and microcomputed tomography analysis to evaluate the effect of Wnt10b on BMP9-induced osteogenic differentiation. Meanwhile, PCR, Western blot analysis, chromatin immunoprecipitation, and immunoprecipitation were used to analyze the possible relationship between BMP9 and Wnt10b. We found that BMP9 upregulates Wnt10b in C3H10T1/2 cells. Wnt10b increases the osteogenic markers and bone formation induced by BMP9 in C3H10T1/2 cells, and silencing Wnt10b decreases these effects of BMP9. Meanwhile, Wnt10b enhances the level of phosphorylated Smad1/5/8 (p-Smad1/5/8) induced by BMP9, which can be reduced by silencing Wnt10b. On the contrary, Wnt10b inhibits adipogenic markers induced by BMP9, which can be decreased by silencing Wnt10b. Further analysis indicated that BMP9 upregulates cyclooxygenase-2 (COX-2) and phosphorylation of cAMP-responsive element binding (p-CREB) simultaneously. COX-2 potentiates the effect of BMP9 on increasing p-CREB and Wnt10b, while silencing COX-2 decreases these effects. p-CREB interacts with p-Smad1/5/8 to bind the promoter of Wnt10b in C3H10T1/2 cells. Our findings suggested that Wnt10b can promote BMP9-induced osteogenic differentiation in MSCs, which may be mediated through enhancing BMP/Smad signal and reducing adipogenic differentiation; BMP9 may upregulate Wnt10b via the COX-2/p-CREB-dependent manner.

Liao YP ，Du WM ，Hu Y ，Li FS ，Ma Y ，Wang H ，Zhu JH ，Zhou Y ，Li Q ，Su YX ，He BC ... -  《-》

Smads, p38 and ERK1/2 are involved in BMP9-induced osteogenic differentiation of C3H10T1/2 mesenchymal stem cells.

Xu DJ ，Zhao YZ ，Wang J ，He JW ，Weng YG ，Luo JY ... -  《-》

Dickkopf-1 is involved in BMP9-induced osteoblast differentiation of C3H10T1/2 mesenchymal stem cells.

Lin L ，Qiu Q ，Zhou N ，Dong W ，Shen J ，Jiang W ，Fang J ，Hao J ，Hu Z ... -  《-》